航空航天镁合金铸件生产制造企业在对铸件的示踪探伤检测时会产生荧光废水。该废水由矿物油、表面活性剂、荧光剂和多种有机物组成,成分复杂,难以处理。为此,基于化学破乳法,探究高化学需氧量(COD)浓度荧光废水的处理可行性。选用破乳剂种类、破乳剂加药量和pH值进行单因素试验,探究各因素对处理效果的影响,通过正交试验,优选出最佳破乳剂为PR-2破乳剂,使用条件为pH=7、破乳剂投加量为3 g/L;选用搅拌速度、搅拌时间以及沉降时间进行单因素试验,优化破乳反应条件,再通过正交试验,得出破乳最佳条件:以100 r/min的速度搅拌30 min,再沉降30 min。在上述条件下,废水COD浓度从2 406.0 mg/L降到233.8 mg/L,COD去除率达90.26%,处理后废水水质达到“污水综合排放标准”(GB 8978-1996)三级标准。
The aerospace magnesium alloy castings manufacturing companies use tracer flaw inspection for castings, which generates fluorescent wastewater. This wastewater consists of mineral oil, surfactants, fluorescent agents, and many organic substances. Its composition is complex and difficult to treat. In this paper, the feasibility of treating fluorescent wastewater with high chemical oxygen demand (COD) concentration based on the chemical demulsification method was investigated. Single-factor experiments were conducted with selected demulsifier types, demulsifier dosage and pH to investigate the effects of each factor on the treatment effect; and through orthogonal experiments, the best demulsifier was found to be PR-2 demulsifier, with pH=7 and demulsifier dosage of 3 g/L. Single-factor experiments were conducted with stirring speed, stirring time and settling time to optimize the reaction conditions for the demulsification method. The best conditions for demulsification were then obtained through orthogonal experiments: stirring at 100 r/min for 30 min and settling for 30 min. Under the aforementioned conditions, it was observed that the wastewater COD concentration decreased from 2 406.0 mg/L to 233.8 mg/L, and the COD removal rate reached 90.26%. The water quality of the treated wastewater was found to meet the tertiary standard of the Comprehensive Sewage Discharge Standard (GB 8978-1996).
